Mazda Motor Corp.

Koichi Hamada, an economic adviser to Japanese Prime Minister Shinzo Abe, told South Korea to adjust its own monetary policies if officials are concerned at the effects of a yen weakened by unprecedented easing.

The yen weakened beyond 100 per dollar for the first time in four years as the Bank of Japan’s deflation-fighting measures have the currency headed for its longest streak of monthly losses in almost two decades.